1. Field of the Invention
The present invention relates to an ultrasonic measurement apparatus that acquires tomographic images or three-dimensional images of an object to be measured by using ultrasonic waves, and more particularly, it relates to an ultrasonic measurement apparatus that acquires a strain characteristic and an elastic property of a sample.
2. Description of the Related Art
An apparatus for acquiring tomographic images by using conventional general ultrasonic waves is constructed to include, as its components, a transmitting unit for transmitting an ultrasonic wave to an object to be measured (sample), a receiving unit for receiving a reflection wave, a scanning unit for scanning the transmitted and received waves, and a unit for converting and visualizing the received reflection signal into a corresponding luminance signal. The interior of the sample is observed by using time series tomographic images acquired by these components. In addition, in one form of the apparatus, three-dimensional images are obtained by scanning an ultrasonic wave in the up and down directions as well as in the right and left directions by means of the above-mentioned scanning unit.
In recent years, there have also been studied a method of generating a strain in the interior of a sample in an artificial manner by compressing a surface of the sample, and measuring the strain by processing ultrasonic signals, or a method of imaging an elastic modulus such as Young's modulus, etc.
In the specification of U.S. Pat. No. 5,178,147, it is described that the elastic property of a sample is measured by compressing the sample in a vertical direction and measuring a relative positional change of each point or location. In addition, in a case where the sample, being an elastic member, has motion of its own, it is possible to measure a strain only by means of the processing of ultrasonic signals without performing such a compressing operation as described above.
In addition, Japanese Patent Application Laid-Open No. H 9-313486 discloses a method of measuring a variation in the thickness of a cardiac muscle based on a relative positional variation between two points of a cardiac wall.